This invention relates to a disc array connection system, a detection method of malfunctioning device and a recording medium having a control program recorded thereon. More particularly, it relates to a method of detecting a malfunctioning device in a connection system in which a host device and a plurality of disc array devices are interconnected by FC-AL (fiber channel-arbitrated loop).
Up to now, the FC-AL connection is realized in this type of the system by connecting an initiator host 2 and target disc arrays 3-1 to 3-3 to a FC-AL concentrator 4, as shown in FIG. 16.
In this case, the initiator host 2 and the target disc arrays 3-1 to 3-3, respectively connected to the FC-AL concentrator 4, logically appear as if the initiator host 2 and the target disc arrays 3-1 to 3-3 constitute a loop, rather than being connected in one-to-one correspondence.
If, in the above-described system, a malfunction occurs in one of the target disc arrays 3-1 to 3-3 constituting the loop, it may appear as if the malfunction has occurred in all of the devices.
The following problems have been encountered in the course of the investigations toward the present invention.
If, in the above-described conventional disc array connection system, an malfunction has occurred in any one of plural disc array devices constituting the FC-AL loop, it may appear as if the malfunction has occurred in the totality of devices. Therefore, the hysteresis of malfunctions of the totality of devices needs to be analyzed to identify the particular device suffering from malfunctions. Therefore, the device suffering from malfunctions can be identified only with considerable difficulties by a time-consuming operation.
Accordingly, it is an object of the present invention to provide a disc array connection system, a method of detecting a malfunctioning device and a recording medium having control program recorded thereon, in which the device suffering from malfunctions can be identified easily in a shorter time.
In a first aspect of the present invention there is provided a disc array connecting system in which a host device and a plurality of disc array devices are connected to a concentrator to interconnect the host device and the disc array devices in a loop logically. The concentrator includes switching circuit which interconnects the host device and the plural disc array devices and a controller which controls the switch circuit so that, on occurrence of a malfunction, only the disc array devices other than the malfunctioning device will be connected to the host device.
According to a second aspect of the present invention, there is provided a method of detecting a malfunctioning device in a disc array connecting system in which a host device and a plurality of disc array devices are connected to a concentrator to interconnect the host device and the disc array devices in a loop logically. The concentrator includes a step of controlling the switching circuit adapted to interconnect the host device and the disc array devices on malfunction occurrence so that only the disc array devices other than the malfunctioning device will be connected to the host device.
In a third aspect of the present invention, there is provided a computer readable program product which comprises a malfunctioning device detection control program. The program is adapted to cause the concentrator to detect a malfunctioning device, in a disc array connecting system in which a host device and a plurality of disc array devices are connected to a concentrator to interconnect the host device and the disc array devices in a loop logically. The malfunctioning device detection control program causes the concentrator to control the switch means adapted to interconnect the host device and the disc array devices on malfunction occurrence so that only the disc array devices other than the malfunctioning device will be connected to the host device.
The program product may be carried by any medium (static or dynamic and may be in the form of e.g., a carrier wave-medium) in a fashion readable by a computer. The medium may be a recording medium.
Specifically, with the disc array connecting system according to the present invention, a switch circuit for interconnecting an initiator host and a plurality of target disc arrays is provided in an FC-AL concentrator 1. On occurrence of a malfunction, an FC-AL loop is transiently disconnected by changing over a switch in the concentrator in the loop. The initiator host 2 and the disc array devices are sequentially interconnected one-by-one for investigation in order to identify a malfunctioning device. The device thus identified is disconnected from the loop to constitute the loop by the remaining devices.
This enables a malfunctioning device to be identified easily, while enabling shortening of the time involved in the identification processing. By changing over the switch connected to the malfunctioning device to disconnect the malfunctioning device automatically from the loop, input/output to the devices other than the malfunctioning device can be continued without affecting these other devices.